From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jacob Keller <jacob.e.keller@intel.com>
Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH] vhost: use struct_size and size_add to compute flex array sizes
Date: Mon, 27 Feb 2023 16:53:53 -0500 [thread overview]
Message-ID: <20230227165340-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20230227214127.3678392-1-jacob.e.keller@intel.com>
On Mon, Feb 27, 2023 at 01:41:27PM -0800, Jacob Keller wrote:
> The vhost_get_avail_size and vhost_get_used_size functions compute the size
> of structures with flexible array members with an additional 2 bytes if the
> VIRTIO_RING_F_EVENT_IDX feature flag is set. Convert these functions to use
> struct_size() and size_add() instead of coding the calculation by hand.
>
> This ensures that the calculations will saturate at SIZE_MAX rather than
> overflowing.
>
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Cc: virtualization@lists.linux-foundation.org
> Cc: kvm@vger.kernel.org
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Will merge, thanks!
> ---
>
> I found this using a coccinelle patch I developed and submitted at [1].
>
> [1]: https://lore.kernel.org/all/20230227202428.3657443-1-jacob.e.keller@intel.com/
>
> drivers/vhost/vhost.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index f11bdbe4c2c5..43fa626d4e44 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -436,8 +436,7 @@ static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
> size_t event __maybe_unused =
> vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
>
> - return sizeof(*vq->avail) +
> - sizeof(*vq->avail->ring) * num + event;
> + return size_add(struct_size(vq->avail, ring, num), event);
> }
>
> static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
> @@ -446,8 +445,7 @@ static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
> size_t event __maybe_unused =
> vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
>
> - return sizeof(*vq->used) +
> - sizeof(*vq->used->ring) * num + event;
> + return size_add(struct_size(vq->used, ring, num), event);
> }
>
> static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
> --
> 2.39.1.405.gd4c25cc71f83
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
prev parent reply other threads:[~2023-02-27 21:54 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-27 21:41 [PATCH] vhost: use struct_size and size_add to compute flex array sizes Jacob Keller
2023-02-27 21:53 ` Michael S. Tsirkin [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230227165340-mutt-send-email-mst@kernel.org \
--to=mst@redhat.com \
--cc=jacob.e.keller@intel.com \
--cc=kvm@vger.kernel.org \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).